In the reaction C2O2−4+MnO−4+H+⟶Mn2++CO2+H2O the reductant is
C2O2−4
MnO−4
Mn2+
H+
C2O2−4+MnO−4+H+⟶Mn2++CO2+H2O In this reaction C2O2−4 act as a reducing agent.